This project seeks to develop new statistical techniques for problems in human development and to apply existing techniques to those problems in novel ways. Work continues in understanding the birth weight distribution in human populations. We have recently elucidated a process of round-off, conversion from ounces to grams, and grouping into weight classes that induces an artifactually jagged frequency polygon in United States birth weight distributions displayed in 100-g bins compared to those from countries where the original weight units are grams. - birthweight, round-off error, unit conversion, misclassification